How long does a septic system last?

Category: Septic system
24 Jan 2023

How long does a septic system last? On average, a new septic system will last for 20-30 years. But this figure is not cast in stone. How long a septic system lasts is influenced by a variety of factors. For starters, durable septic systems are those that were properly built and are well maintained.

The following are some of the main factors that affect the longevity of a septic system:

The number of people – the general assumption is that at least 110 gallons of water per bedroom is used every day in the average home. In other words, the more the bedrooms you have, the more wastewater your septic system will have to handle. If the septic tank receives too much water at short intervals, the wastewater might be forced out of the septic tank and into the drain field before the bacteria finish breaking down the organic waste or before the other solids settle down. These solids might, therefore, end up in the drain field which can cause the system to fail.

The products you use – some of the household products have chemical pollutants that can be toxic to the beneficial bacteria in the septic system. The more a septic system owner uses these harmful products, the more the septic system is affected. By and large, the products you use at home will directly impact on the overall health and longevity of your septic system

Soil quality – the quality of soil will determine how durable your septic tank is. For instance, acidic groundwater can corrode a concrete septic tank. This is why an engineer should inspect your property in order to recommend the best septic system to install.

The 20-30 year period is the national lifespan average of septic systems in Canada. However, it is possible for the tanks to last for even up to 50 years or more depending on the soil conditions and how well the owner takes care of it.

How long does a septic system drain field last?

A well-built and properly maintained drainfield should last for at least 20 years.  But there are some factors that determine exactly how long the septic drain field will last. These are:

How it was installed – the details of the installation of the leachfield will determine its longevity. Some important details include the depth of the water table, dimensions of the leachfield, and the type of gravel used.

Effluent discharge system – the method the septic system uses to discharge effluent can also determine how long the drainfield lasts. Some discharge mechanisms might overload the drainfield with too much wastewater and this reduces the percolation rate.

Soil conditions – the soil condition affects the rate of percolation in the drainfield area and if the percolation rate is not too good, the drainfield will not last long. Other important soil conditions include seasonal flooding, surface runoff, and groundwater levels.

Maintenance – a septic drain field that is maintained regularly lasts longer than the one that is neglected.  Maintenance includes pumping the tank every couple of years and adding biological additives periodically.


Why do septic systems fail?

The septic tank is responsible for separating the solid organic waste from the liquid wastewater. Solid particles settle at the bottom of the tank forming the sludge while grease settles at the top forming the scum layer. As effluent flows from the tank into the drain field, some solids escape with the wastewater and over time, these solids cause the leach field to clog up. A clogged leach field cannot receive any more effluent and this leads to backups, odors and other characteristics of a failed septic system. Suffice it to say that all septic systems eventually fail just from normal use.

How to perform a septic inspection

If your system fails and ends up polluting the environment, the government will require you to replace it completely. It is, therefore, a good idea to inspect your system regularly to ensure it is working properly. But exactly how can you perform a septic inspection? Well, start by looking for the following tell-tale signs of a failing system:

  • Drains that empty slowly
  • Sewage backing up into the house
  • Wet and smelly spots in the yard
  • When you expereince problems with the drains when it rains
  • If you have to pump the tank frequently – more than once a year
  • If grass appears greener around the septic tank

Using tracer dye tables to perform a septic inspection

If you see any of the above signs, your septic system is most likely failing and you need to deal with it before it gets out of hand.  Another easy way to perform a septic inspection is to use the dye tracer tablets. These are septic friendly tablets that you can flush in the toilet and if your septic system has a problem, the dye will appear on the grass around your drainfield.

Common septic tank problems and how to solve them

Hydraulic overload

Problem: Hydraulic overload is when too much water is sent to the septic tank at a go. Whenever the tank receives too much water, it is forced to release wastewater prematurely into the drain field. Hydraulic overload, therefore, leads to effluent surfacing on the yard or backups in the house.

Solution: In order to prevent this overload, avoid doing too much laundry in one day and fix any leaks in the fixtures as soon as you notice them.

Poor or no maintenance

Problem: Lack of proper maintenance is a leading cause of premature septic system failures. For instance, if you do not clean the outlet filter regularly, it might get clogged thereby leading to failure of the entire septic system. In a bid to reduce wanton neglect of septic systems, the government has made it mandatory for septic system owners to pump them every couple of years.

Solution: Make sure to pump your septic tank after a couple of years or as is needed. We also recommend adding biological additives periodically to help improve septic system health and efficiency.

Poor design and installation

Problem: Different locations have different soil types, bedrocks, groundwater levels, and gradient. Ignoring such factors when designing the septic system will lead to the design of a system that will cause lots of problems for the owner.

Solution: For best results, the septic system must be designed and installed as per the unique requirements on the property. Make sure to consult a qualified engineer and invite them to do a site inspection in order to furnish you with the information you need to choose the best design for your septic system.

Physical damage

Problem: Driving, paving or constructing over the septic tank can result in physical damage of some important components of the septic tank.  The tank or the pipes might shift or break and this will result in the malfunction or failure of the system.

Solution: Avoid driving, construction or any other physical activity that might exert undue pressure above and around the septic tank

Using harmful products

Problem: Most septic system owners unknowingly use lots of harmful products. Products like bleach, solvents, detergents, drain washers, antibacterial soaps are made from chemicals that can drastically reduce the bacteria and enzyme population in the septic tank. In fact, the average septic system has over a hundred traceable chemical compounds.

Solution: Avoid using products that might harm your septic system. Go through our free eBook which has a comprehensive list of all the products you should avoid

Flushing non-biodegradable items

Problem: Apart from human waste, the only other thing that is safe to flush in the toilet is tissue paper. Unfortunately, people flush all manner of things including condoms, floss, hair, expired pharmaceuticals, and facial tissue. These products contribute to the tank filling up too fast and some of them can even clog up the pipes.

Solution: Do not flush anything in your toilet apart from human waste and tissue paper.

Root damage

Problem: Roots are very intrusive and they will push themselves into the pipes thereby resulting in a clogged up system. Over time, the roots can also burst the pipes as well as cause damage to the septic tank thereby causing leakages.

Solution: As a rule of thumb, avoid planting trees and shrubs near the septic tank.

Can you repair a failed septic system?

A failed septic system is not only a nuisance but also a public health hazard. This is why any problem that occurs in the septic system should be fixed pronto. Septic systems usually fail due to biological or mechanical problems.

Repairing biological problems

Shock treatment is usually sufficient to repair a system that is failing on biological grounds. Most septic system owners unknowingly use products that drastically reduce the population of bacteria in their septic tanks. As a direct consequence, organic waste is not digested quickly enough. As new wastewater from the house enters the septic tank, some of the wastewater in the tank will have to flow into the drain field. Since the bacteria population was reduced by the harmful substances used in the house, some solid waste might escape into the drainfield and that could easily lead to a blocked drainfield. Biological additives introduce billions of bacteria and enzymes and that will help your septic system to continue breaking down the organic waste optimally.  Bio-Sol’s Shock Treatment and keepup products have helped more than 18,000 septic system owners in Canada since 1992.  In over 80% of these cases, the septic systems were repaired and started working optimally again. This saved them in between $10,000 and $40,000! You can take advantage of this product too. Click here for a free quote.


Repairing mechanical problems

Mechanical problems are pretty rare but there is always an exception. If a septic system fails, the first thing you should do is try out a biological solution. More often than not, the biological solution will work and that will save you thousands of dollars. This notwithstanding, mechanical problems still happen. For instance, a concrete tank could get cracked due to poor construction, driving cars and other heavy machinery above the septic tank and even corrosion from gases like hydrogen sulfide which are a by-product of anaerobic bacteria activity. Such issues may result in the concrete tank cracking and these cracks will allow water to seep into the tank or wastewater to leak out before it is treated.  There are two main methods of repairing cracks in concrete septic tanks.

Filling in cracks in lids – cracks in lids are typically caused by driving over them or any other human activity that might exert too much pressure. Cracks in lids are quite easy to fix – concrete filler is applied and that should take care of the crack. However, a cracked lid might mean the concrete tank is damaged too so it’s a good idea to let an engineer inspect it just to make sure all is well.

Repairing cracks in the tank – not all cracks in septic tanks need to be repaired. Very small cracks can be left alone. Concrete septic tanks are made with thick walls so tiny cracks will not cause any harm. The only cracks you need to be worried about are those that are too big or those that are already causing leakage of wastewater. In such a scenario, the tank will be emptied first and then given some time to dry before any repair can be done. Only skilled and licensed contractors should repair septic tanks because specialized equipment and protective gear are required for the job. The contractor will use cement and crack filler to cure the cracks in the tank.

Caution: Do not attempt to repair the tank yourself because entering a septic tank is highly dangerous. Even when empty, the tank will still be emitting hazardous gases which can harm your health or even result in death.

DIY drainfield / septic tank replacement

Some septic system owners decide to take the DIY drainfield approach when they encounter a problem with their system. Usually, this entails draining the wastewater and then digging a bed of rocks as a way of repairing the failed drain field. This or any other form of DIY drainfield repair and replacement is not only dangerous but also illegal. The government requires regular inspections of the septic system and if you do this, an inspector will eventually catch up with you and this could attract a hefty fine.

Septic tank replacement might be necessary if your septic tank is damaged for whatever reason. However, do not attempt to replace the tank yourself because it is quite dangerous. Only skilled and duly licensed contractors should be allowed to perform a septic tank replacement.

If your septic system is messed up to the point that it is causing pollution to the environment, then it will be mandatory not only to replace the tank but also to overhaul the entire septic system.  Just like it is the case in septic tank replacement, replacing the entire system is also a job for the pros. In fact, Canadian environmental law does not allow everyone to install or repair a septic system. Only duly licensed installers can do the job. Replacing the septic system is a huge undertaking and it will cost you anything in the $10,000- $30,000 range. It is, therefore, a good idea to keep your septic system working optimally in order to avoid incurring such exorbitant costs.

How to prolong your septic system life

With proper care and maintenance, your septic system will serve you well for years. Most septic system owners ruin their systems just because of the use of products that harm their systems. The average septic tank has over 100 traceable pollutants which come directly from household products. These pollutants significantly reduce the bacteria population in the septic tank. The depletion of the bacteria pollution means organic waste will not be broken down adequately and this can cause blockages in the drain field thereby leading to a failure of the entire system. The best way to take care of your system is to ensure you avoid using products that are not septic-friendly. Here is a free eBook that has a comprehensive list of all the products that could be harming your septic system: DOWNLOAD THE FREE EBOOK

About the author


CEO at Bio-Sol

Our goal is not only to offer you the best products on the market but also to educate and empower you with the insights you need for successful wastewater treatment.


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